Telephone-exchange system.



R. S. WILBUR.

TELEPHONE EXCHANGE SYS TEM. APPLICATION FILED SEPT. n, 1915.

1,222,342, Patented Apr. 10, 19w.

HOE/6V4 70/ Ray Wi/baw.

by yam onrro" BA"! 55. WILBUR, 03E JERSEY CITY,

NEW JERSEY, ASSIGNOR '10 VJESTEEN ELECTRIC COMPANY, INCORPORATED, 0:? NEW YORK, N. '35., A CORPORATION U75 NEW YORK.

TELEPHONE-EXCHANGE SSZ'STEJME.

Application filed September 11, 1916.

To all whom it may concern:

Be it known that l, RAY S. l/VILBUR, a citizen of the United States, residing at Jen sey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Telephone- EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, its object being the production of improved signaling means for such systems.

In accordance with a feature of this invention a link circuit is provided with a relay operating upon the energization of a supervisory relay, and a second relay operating upon the deenergization of the supervisory relay, and means for thereafter intermittently operating the firstmentioned relay to intermittently complete an operating circuit for the signaling device after subsequent operation of the supervisory relay.

This invention is illustrated in the accompanying drawing in which all apparatus is shown in its normal and unactuated condition.

There is shown in the drawing a telephone exchange system containing one embodiment of this invention and comprising subscribers lines A and B terminating at a central ollice, and a cord circuit C thereat for interconnecting the subscribers lines. It will be understood that a plurality of lines similar to A andB terminate at the central office, but

for the sake of simplicity only the two lines are shown.

It is believed that the invention will be fully understood from a description of the operation of the system shown in the draw ing, and 1t Wlll be so described.

Assuming that subscriber A desires to converse with subscriber B, A signals the central oilice in the usual manner. In response to the signal, the operator inserts the answering plug of the cord circuit G into the jack of As line, whereupon cut-0d relay 5 operates and then answering supervisory relay 6 operates shortly thereafter. Before the operation of the calling supervisory relay 6, the differentially wound relay 7 not operated, for the reason that the circuit of each winding is complete,that for the left-hand winding being from battery Specification of Letters latent.

Patented Apr. 1L6, le l'l. Serial No. 119,482.

through winding 8, left-hand normal contact of relay 9, normal contact of listening key 10 to point 11, and the circuit through the right-hand winding being from battery through winding 12, right-hand normal contact of relay 9, normal contact of relay 7, contact of supervisory relay 6 to point 11, the circuit then extending through resistance 13, sleeve contacts of the plug and jack and the winding of cut-off relay 5 to ground. Upon the operation of the supervisory relay 6, the circuit through winding 12 of relay 7 is opened, whereupon the relay operates, opening its normal and closing its alternate contact.

The operator may now actuate the listening key 10, connecting the operators telephone set to the talking strands of the cord circuit. The operation of this listening key opens the circuit through the winding 8 of relay 7, whereupon this relay releases. Upon being advised that subscriber A desires connection with subscriber B, the operator restores the listening key 10 to normal position and inserts the calling plug of the cord circuit G into the jack of Bs line, whereupon the cut-off relay 14 is operated and calling supervisory lamp 15 is lighted. When listening key 10 is restored to normal position, the circuit through winding 8 of relay 7 is again established, operating this relay. The operator by actuating ringing key 20 may signal subscriber B in the usual manner. 'Subscriber B, in responding, causes the operation of calling supervisory relay 21, which thereupon connects a resistance 22 in shunt of the lamp l5, thereupon elfacing the lamp.

Upon completing the conversation, subscribers A and B r store the receivers to the switch hooks, causing the release of supervisory relays 6 and 21. The release of relay 6 causes the operation of relay 9 over circuit from battery through the winding of relay 9, alternate contact of relay 7, contact of relay 6, resistance 13, sleeve contacts of the answering plug and jack and winding 100 of cut-off relay 5 to ground. Relay 9, in operating, completes a locking circuit for itself from battery through the winding of relay 9, left-hand alternate contact thereof, normal contact of listening key 10, resistance 105 13, sleeve contacts of the answering plug and jack and the winding of cut-01f relay 5 to ground. The answering supervisory lamp 523 and the calling supervisory lamp 15 are lighted to furnish disconnect signals to the operator. The operator may then remove the plugs from the jacks, whereupon all apparatus returns to normal.

Suppose, however, that before the operator removes the plugs from the jacks, subscriber A initiates another call. The removal of the receiver from the switch hook by subscriber A causes the intermittent or periodic lighting of the supervisory lamp 28, thus furnishing a recall signal to the operator. The intermittent operation of supervisory lamp 523 is accomplished in the following manner: Upon the restoration of the receiver to the switch hook by subscriber A, relay 6 releases, and relay 9 operates and locks up in the manner before described. The operation of relay 9, in opening its lefthand normal contact, opens the circuit through winding 8 of relay 7, and in closing its right-hand alternate contact connects an interrupter 24: in circuit with winding 12 of relay 7, whereupon relay 7 is operated inter mittently to close and open its alternate contact. At this time, however, the alternate contact of relay 7 is short-circuited at the contact of relay 6, so the intermittent closure of the alternate contact of relay 7 has noefiect upon the lamp 23. The subsequent energization of supervisory relay 6, in response to the removal of the receiver from the switch hook by subscriber A, opens its contact, whereupon the following intermittently closed operating circuit for the lamp 23 is effective for intermittently lighting the lamp: from battery through the answering supervisory lamp 23, alternate contact of relay 7, left-hand alternate contact of relay 9, normal contact of listening key 10, resistance 13, sleeve contacts of the answering plug and jack and the winding of cut-off relay 5 to ground. The intermittent operation of relay 7 thereupon periodically or intermittently closes the operating circuit just traced, whereupon the lamp 23 will be lighted intermittently. The operator, observing the intermittent lighting of this lamp, will actuate listening key 10 to connect the telephone set to the talking strands of the cord circuit, and in so doing will open the locking circuit of relay 9, which thereupon releases, and in turn releasing relay 7. The operator may now complete any con nection which subscriber A may desire.

What is claimed is:

1. A telephone exchange system comprising a telephone line, a link circuit connected with the line, a supervisory relay therefor controlled over the line, a primary relay operating upon the energization of the super.- visory relay, a second relay operating upon the deenergization of the supervisory relay while the primary relay is energized, a locking circuit for the secondary relay completed upon its energization for rendering this relay independent of the supervisory and primary relays, means for intermittently or periodically operating the primary relay while the secondary relay is locked up, a signaling device, and an operating circuit for the signaling device intermittently closed by the intermittent operation of the primary relay when the supervisory relay is energized.

2. A telephone exchange system comprising a telephone line, a link circuit connected therewith, a. supervisory relay therefor controlled over the line, a primary relay operating upon the energization of the supervisory relay, a secondary relay conditioned for operation by the operation of the primary relay and operated by the deenergization of the supervisory relay, means for intermittently operating the primary relay brought into circuit therewith by the operation of the secondary relay, a signaling device, and an operating circuit for the signaling device intermittently closed by the intermittent operation of the primary relay when the supervisory relay is energized.

3. A telephone exchange system comprising a telephone line, a link circuit connected with the line,'a supervisory relay therefor controlled over the line, a primary relay operating upon the energization of the supervisory-relay, a secondary relay conditioned for operation by the operation of the pri mary relay and operated by the deenergization of the supervisory relay, means for intermittently operating the primary relay brought into circuit therewith by the operation of the secondary relay, a signaling device, and an operating circuit for the signaling device jointly controlled by the supervisory relay and the intermittently operating primary relay.

t. A telephone exchange system comprising a telephone line, a link circuit connected therewith, a. supervisory relay therefor controlled over the line, a primary relay, a secondary relay, an energizing circuit therefor jointly controlled by the primary and supervisory relays, a locking circuit for the secondary relay established upon the energization thereof, means for intermittently operating the primary relay brought into circuit therewith upon the energization of the secondary relay, a signaling device, and an operating circuit for the signaling device jointly controlled by the supervisory relay and the intermittently operating primary relay.

5. A telephone exchange system compris ing a telephone line, a link circuit connected therewith, a supervisory relay therefor con trolled over the line, a primary relay, a secondary relay, an energizing circuit therefor jointly controlled by the primary and supervisory relays, means for intermittently operating the primary relay brought into circuit therewith upon the energization of the secondary relay a signaling device, and an intermittent operating circuit for the signaling device partially established by in- Gopies of this patent may be obtained for five cents each, by addressing the termittent energization of the primary relay and completely established by the energization of the supervisory relay.

In Witness whereof, I hereunto subscribe my name this 8th day of September A. D.,

RAY S. WILBUR.

Commissioner of Patents,

Washington, 1). G. 

